How does HowBridge use Chunghwa Post data to check your delivery address?
Which Chunghwa Post service does HowBridge use to verify delivery addresses?
It uses the WebAPI of Chunghwa Post's National Standard Delivery Address platform (NSDA). On 2026-09-22 HowBridge received a system notice from Chunghwa Post that "the WebAPI service has completed review", and it went live on the production site on 2026-09-23. When a member enters a Taiwan delivery address, the HowBridge server first removes the floor and then calls GetPostAddrNo (set to "match against the postal addresses on record at Chunghwa Post"). If Chunghwa Post has the address on record, the screen shows the postal standard address and the 6-digit postal code is stored with the recipient record. If it is not on record, or the service is temporarily unreachable, the system falls back to Ministry of the Interior TGOS house-number matching. In the 2026-10-05 tests, addresses on record were answered in about 0.4–0.7 seconds. The check does not hard-block saving: if the service is unreachable you can save as usual, and if no match is found you can tick the confirmation box and save. Approval also does not mean government certification or endorsement of HowBridge.
This is a check HowBridge runs on the Taiwan home-delivery address field to reduce delivery problems caused by mistyped addresses. It is not government certification: Chunghwa Post reviewed HowBridge's WebAPI integration application, which is not an endorsement of HowBridge's services. Chunghwa Post's website also states that 3+3 postal code lookup results are "for reference when writing addresses on mail and for use by Chunghwa Post's mail-processing units in sorting mail only". A "postal standard address" match does not guarantee that a parcel will be delivered; delivery remains the responsibility of the courier or convenience-store operator that actually carries it. HowBridge only offers mainland China → Taiwan consolidation shipping, its only warehouses are the Shenzhen consolidation warehouse and the Taoyuan Dayuan operations warehouse, and it does not offer purchasing-agent services.
How did HowBridge obtain the Chunghwa Post NSDA WebAPI?
The National Standard Delivery Address platform is a website built by Chunghwa Post that offers standard postal address lookup, batch conversion and a WebAPI. The official description says the WebAPI is "currently available to registered members" and is limited to members and bound to an IP address. Here is how HowBridge applied and went live:
| Item | Details |
|---|---|
| How we applied | Logged in to the platform as an EZPost member, entered the integration IP of the HowBridge server under "Use and Change Application" and submitted it (following the process in Chunghwa Post's front-end user manual) |
| Review result | On 2026-09-22 we received a Chunghwa Post NSDA system notice: "WebAPI service has completed review" |
| Go-live | Enabled on the HowBridge production site on 2026-09-23; the key is stored only on HowBridge's Taiwan server and is never placed in web pages, the app or LINE |
| API in use | GetPostAddrNo (standard postal address, looked up by address), with the isStandard parameter set to 1 |
| API not in use | GetPostAddr (coordinates from an address code): in a 2026-09-23 test with the production key it gave no response for a long time, so coordinates now come from Ministry of the Interior TGOS |
| Entry points covered | Recipient settings in the website member center, the HowBridge app and the LINE official account are all checked by the same server |
Chunghwa Post reviewed HowBridge's WebAPI integration application (an integration IP must be registered when applying); only after review could the API be used. This is not government certification or endorsement of HowBridge, nor does it constitute cooperation with, certification of, or endorsement of HowBridge by Chunghwa Post. Every mention of "approval" on this page refers to this WebAPI application.
What does NSDA return? What do postal record, 6-digit postal code and standard postal address mean?
The official documentation says GetPostAddrNo "takes an address and returns the postal code, standard postal address and address code for that address". When isStandard is set to 1 it "matches against the postal addresses on record at Chunghwa Post", and if the address is not on record it returns an empty address code. HowBridge decides as follows:
| Returned field | Official name | How HowBridge uses it |
|---|---|---|
ZipCode | Postal code | When the address is on record this is 6 digits (3+3) and is stored with the recipient record; when it is not on record it may return 3 or 6 digits, which are never used |
PostAddr | Standard postal address | Starts with the 6-digit postal code, followed by the address including village (li) and neighborhood (lin); HowBridge strips the leading postal code and shows the rest in the check result |
PostAddrNo | Address code | A value means Chunghwa Post has the address on record (check passed); an empty string means not on record. HowBridge does not store the address code |
How do I read a 6-digit postal code?
Chunghwa Post has used the "3+3 postal code" since 2020-03-03. According to the official explanation, the first 3 digits follow the administrative district of the delivery post office, and the last 3 digits are the delivery-segment sequence number. So the first 3 digits do not always match the district where the address is located; for example, the official Q&A mentions that Wugong Road in Xinzhuang District, New Taipei City, has the first 3 digits 248.
How does a standard postal address differ from what I typed?
A standard postal address adds the village (li) and neighborhood (lin) and normalizes the city/county and number formats. For example, entering 桃園市大園區拔子林三路30巷8號 returns 桃園市大園區菓林里31鄰拔子林三路30巷8號 from Chunghwa Post. HowBridge only displays this as a check result and never changes the address you entered automatically.
How does the system check an address as you fill it in? How do Chunghwa Post and TGOS divide the work?
In the website member center, the system checks in the background about 0.8 seconds after you stop typing; on the LINE official account it checks before you confirm the recipient details; and it checks once more in the background after you save. The order is as follows: Chunghwa Post first, and Ministry of the Interior TGOS only if Chunghwa Post finds nothing:
| Order | What is queried | Result |
|---|---|---|
| 1 | Chunghwa Post NSDA GetPostAddrNo (floor removed first) | On record → shows "郵政標準地址" ("Postal standard address") and the standard address, and stores the 6-digit postal code; coordinates are then obtained from TGOS |
| 2 | Ministry of the Interior TGOS exact house-number match | Only queried when Chunghwa Post has no record or cannot be reached; if found → shows "已比對到門牌地址" ("House-number address matched") |
| 3 | Ministry of the Interior TGOS fuzzy match (limited to the selected city/county and district) | If a similar house number is found → shows "您是不是要找：" ("Did you mean:") with candidate addresses that you can apply in one click |
| 4 | Ministry of the Interior TGOS nationwide match (sends only the road and house-number part, without city/county or district) | You may have picked the wrong city/county or district → candidates in other cities/counties are listed |
| 5 | Nothing found | Shows "查無此門牌，請確認縣市、區域與門牌號碼是否正確" ("No such house number found; please check the city/county, district and house number"); after ticking "我確認地址正確" ("I confirm the address is correct") you can still save |
Why does Chunghwa Post come first?
Chunghwa Post's response carries both the 6-digit postal code and the postal standard address, whereas TGOS house-number matching does not return a postal code. A result of "not found" is only given when both fail to find the address; a miss at Chunghwa Post alone does not count as not found, because the official coverage of Chunghwa Post's records is not published.
What happens if Chunghwa Post cannot be reached?
Each Chunghwa Post query waits at most 3 seconds and each TGOS query at most 4 seconds, with a maximum of 8 seconds for the whole check. If Chunghwa Post has 3 consecutive timeouts, connection failures, server errors, rate limits or access denials within 15 minutes, the system pauses calls to it for 5 minutes and uses TGOS only. If both are temporarily unavailable, no check result is shown, and you can still save right away.
Is the address checked again after saving?
Yes. After you save, the system checks once more in the background and stores the check status, data source, standard address and 6-digit postal code with that recipient record. The member center currently shows only the standard postal address, not the 6-digit postal code; the "postal code" field on the form is filled in automatically from the district you selected and is not the 6-digit code obtained from the check.
Test results: which addresses were found and which were not?
On 2026-10-05 we called Chunghwa Post's GetPostAddrNo (isStandard=1) directly from the HowBridge server. Every call returned HTTP 200, with response times of 288–912 milliseconds. The examples use public road house numbers and contain no member data:
| Address entered | Chunghwa Post response | Notes |
|---|---|---|
| 桃園市大園區拔子林三路30巷8號 | On record; postal code 337013; address code 3370026182; standard address 桃園市大園區菓林里31鄰拔子林三路30巷8號 | The standard address adds the village (li) and neighborhood (lin) |
| 桃園市大園區拔子林三路30巷8號3樓 | Not on record (empty address code), though the postal code still returns 337013 | Addresses with a floor often are not found (3F is not on record in this case), so the system removes the floor before querying |
| 臺北市大安區金山南路二段55號 | On record; postal code 106409; address code 1061184876 | Standard address 臺北市大安區永康里10鄰金山南路二段55號 |
| 台北市大安區金山南路二段55號 | On record, same result as above | Both common written forms of the "Tai" in Taipei are found |
| 臺北市大安區金山南路二段５５號 | On record, same result as above | Full-width digits are also found |
| 臺北市大安區金山南路2段55號 | On record, same result as above | Section 2 is found whether written with an Arabic numeral or a Chinese numeral |
| 臺北市大安區金山男路二段55號 | Not on record; the postal code returns only 106 | A typo in the road name is not found |
| 臺北市大安區金山南路二段9999號 | Not on record; the postal code returns 106004 | The road section exists but the house number does not |
| 臺北市大安區金山南路二段 | Not on record; the postal code returns only 106 | No house number; HowBridge does not send this kind of query and prompts you to add the house number instead |
| 臺北市大安區查無此路999號 | Not on record; the postal code returns only 106 | A road name that does not exist |
| 新竹縣北埔鄉拔子林三路30巷8號 | Not on record; the postal code returns only 314 | Wrong city/county and township selected; the system then uses TGOS nationwide matching to find the likely correct city/county |
| 桃園市中壢區中山路100號 | Not on record; the postal code returns 320676 | TGOS matched this house number in a 2026-09-21 test, showing that "not on record at Chunghwa Post" does not mean the address does not exist |
1. A floor often makes the lookup fail (3F is not on record in this case, although we have previously seen a 1F address that was still found), so the system removes the floor before sending the address to Chunghwa Post; the floor you entered is still saved. 2. Most writing variants are still found: both written forms of "Tai" in Taipei, full-width digits and Arabic-numeral section numbers all match the same address code. 3. Not on record does not mean it is wrong: the Zhongli example is found in TGOS, so the system goes on to match with TGOS and never concludes "not found" from Chunghwa Post alone.
How do members use the postal address check?
There is nothing to apply for or set up; the check runs automatically when you enter a delivery address:
1Choose the city/county and district
In the member center, add or edit a recipient and first choose the city/county and the township or district.
2Enter the road and house number in the address field
Enter the address up to the house number; you can still enter the floor as usual. If you enter only the city, county and district without a house number, the system prompts "請在地址欄填寫路名與門牌號碼" ("Please enter the road name and house number in the address field").
3Read the check result
A green "郵政標準地址" ("Postal standard address") means Chunghwa Post has the address on record; when candidate addresses appear you can press "套用" ("Apply"); if nothing is found, please re-check the city/county, district and house number.
4Save
Save once you have confirmed. If nothing was found but you are sure the address is correct, tick "我確認地址正確" ("I confirm the address is correct") and save. You can also set recipients through the recipient menu of the HowBridge LINE official account.
Where is my address sent, and how long is it kept?
A delivery address is a "means of contact" under Article 2 of the Personal Data Protection Act and is therefore personal data. HowBridge uses it only for the purpose of delivery:
| Item | How it is handled |
|---|---|
| What is sent to Chunghwa Post | Only the address text (city/county + district + road and house number, with the floor removed); no recipient name, phone number or identity data |
| What is sent to Ministry of the Interior TGOS | The address text (city/county + district + road and house number, including the floor), likewise without name or phone number |
| Temporary caching of results | Results that passed or returned candidates are cached for 30 days and not-found results for 1 day, to avoid repeating the same lookup; results answered only by TGOS because Chunghwa Post was temporarily unreachable are cached for only 6 hours; results where no check was possible at all are not cached |
| System logs | Error logs record only the data source and error code, never member addresses or URLs containing keys |
| Google Street View preview | After the check passes (or you tick the confirmation, or the check is temporarily unavailable), the website member center has your browser send the address text to the Google Street View service to show a preview of the entrance; the privacy policy also explains that the server side may send the address coordinates to Google to look up Street View |
| Privacy policy | The privacy policy already discloses that address checking and map services use Chunghwa Post, Ministry of the Interior TGOS and Google |
What are the limitations of this check?
The check catches many mistyped addresses, but it is not a cure-all:
Not on record does not mean the address does not exist
The official coverage of Chunghwa Post's records is not published. New buildings, newly assigned house numbers or special addresses may not be on record yet, so the system also matches with TGOS and only reports not found when neither finds the address.
Passing is not a guarantee of delivery
Chunghwa Post states that 3+3 postal code lookup results are for reference when writing addresses on mail and for mail sorting only. The check only confirms that the way the address is written matches the data; the recipient's name, phone number, building-management receiving and so on still need to be confirmed by you.
The 3+3 postal code Web Service application is still pending
Chunghwa Post has a separate 3+3 postal code Web Service that requires a paper application and review. HowBridge has submitted the application, but it has not been approved and is not enabled; the 6-digit postal codes now used come only from addresses that NSDA found on record.
Only Taiwan home-delivery addresses are checked
Convenience-store store-to-store pickup addresses are filled in from store data and are not checked separately; HowBridge also only handles delivery addresses in Taiwan.
When Chunghwa Post's service has problems
On the night of the 2026-09-23 launch the NSDA side returned errors, and all checks automatically switched to TGOS at that time. If this happens again you can still save; the screen will simply show the TGOS house-number matching result or no result.
How much does a correct address matter for delivery? What research can I refer to?
The studies and reports below provide background. None of them is about HowBridge or Taiwan consolidation shipping; the figures come from other countries and cannot be applied directly to your parcel:
- Address errors and returns: two USPS Office of Inspector General reports found that in both FY2013 and FY2014, 4.3 percent of mail was undeliverable as addressed (UAA), costing the Postal Service nearly $1.5 billion a year to process and about $20 billion across the industry; the main causes were moves without an address update and uncorrected senders' mailing lists. A Universal Postal Union white paper also records that 40% of the addresses in a Costa Rican business-customer database were incorrect.
- The value of a standard address database: a UK PAF report estimates that the Postcode Address File brings the UK £992m – £1.38bn a year, with e-commerce misdelivery costs of about £100m; the UPU white paper records that Denmark's opening of official address data in 2005–09 produced direct benefits of about 90 million USD against costs of about 3 million USD. This shows that complete, open standard address data has quantifiable economic benefits (the PAF report itself says its estimates are speculative).
- Last-mile delivery failure: van Duin et al. (2016) found in Dutch data that only 75% of first deliveries succeeded, mainly because the recipient was not at home; Edwards et al. (2010) simulated that a second delivery attempt raises per-parcel carbon emissions by 9% to 75%, and most of the extra emissions come from recipients collecting the parcel themselves. Both studies are about recipients not being home; failures caused by wrong addresses need to be supported separately by postal UAA data.
- Address standardization and Chinese address matching: Churches et al. (2002) showed that addresses must be standardized before matching; Tian et al. (2016) and Lin et al. (2019) point out that Chinese addresses have no delimiters and many writing styles, so they need to be broken into components or matched with semantic models; Lin et al. tested on a Shenzhen address database and reached an F1 of 0.97. A 2022 report by Taiwan's Ministry of the Interior Department of Statistics explains that house-number addresses and postal addresses are not necessarily identical and includes Chunghwa Post's standard postal addresses.
- Human-factors research on real-time form validation: Bargas-Avila et al. (2007) found that error messages popping up while a form is being filled in are often ignored; Seckler et al. (2012, n = 303) showed that error messages are better placed next to the field in error, with the right side most preferred; Seckler et al. (2014, N = 65) showed that improving a form according to guidelines speeds up completion and reduces the number of submission attempts. HowBridge places its check prompt directly below the address field and asks you to confirm an address that was not found before saving, which can be compared with these studies.
- No quantitative study of address checking for Taiwan consolidation parcels was found: we found no academic paper or government report measuring how the return rate or delivery-failure rate of Taiwan delivery addresses changes after a postal standard address check, and no related Taiwan thesis either; all quantitative figures cited on this page come from the United States, the United Kingdom, the Netherlands, Costa Rica, Denmark and Shenzhen, and should be treated as indirect evidence for Taiwan.
What are the common terms in postal address checking?
- National Standard Delivery Address platform (NSDA)
- A website built by Chunghwa Post that offers standard postal address lookup and printing, batch conversion and a WebAPI; the WebAPI is limited to registered members and bound to an IP address.
- Standard postal address
- The address format organized by Chunghwa Post, starting with a 6-digit postal code and including the village (li) and neighborhood (lin).
- Address code (PostAddrNo)
- The code NSDA assigns to an address on record; when isStandard is set to 1, an address that is not on record returns an empty address code.
- 3+3 postal code
- The 6-digit postal code used by Chunghwa Post since 2020-03-03: the first 3 digits follow the administrative district of the delivery post office, and the last 3 are the delivery-segment sequence number.
- Postal record
- Means that Chunghwa Post's postal address data contains the address; this page judges it by whether the address code has a value.
- TGOS house-number matching
- The Ministry of the Interior TGOS platform's nationwide house-number location matching service, which returns house-number coordinates and not a postal code; HowBridge has used it since 2026-09-21.
- WebAPI
- An interface that lets programs make calls over the network; the HowBridge server uses it to query Chunghwa Post for addresses, and the member's browser never connects to Chunghwa Post directly.
- Integration IP
- The server network address registered when applying for the WebAPI; the NSDA key is bound to this address.
What are the sources and the scope of verification?
The sources below were consulted on 2026-10-05; document dates and consultation dates are labeled separately, and dates not stated in a document are not invented.
Official and government primary sources
- Chunghwa Post: National Standard Delivery Address platform, Web API service｜Document date: 2020-11-19; the official page lists two APIs: GetPostAddrNo "takes an address and returns the postal code, standard postal address and address code for that address" and GetPostAddr, a lookup by address code; isStandard=1 "requires matching against the postal addresses on record at Chunghwa Post... if the address is not on record, an empty address code is returned"; APIKey "service is limited to members and bound to an IP". The date is the API's listing date.
- Chunghwa Post: National Standard Delivery Address platform, user guide｜Document date: not stated; official FAQ: the Web API "lets users query standard postal addresses through an API, currently with 2 APIs" and "is currently available to registered members"; unregistered users can only do single lookups and printing.
- Chunghwa Post: National Standard Postal Address Management System project, front-end user manual｜Document date: 2021-07-28; Web API application process: click "EZPost member login" → member data maintenance → "Use and Change Application" → "enter the integration IP, then click apply".
- Chunghwa Post: postal code lookup (3+3 postal code lookup)｜Document date: 2026-10-01; the official site's 3+3 lookup directs users to the "National Standard Delivery Address platform" and states that results are "for reference when writing addresses on mail and for use by this company's mail-processing units in sorting mail only (please do not use as a basis for writing for any other purpose)".
- Chunghwa Post: customer Q&A "Why are the first 3 digits of the postal code for Wugong Road, Xinzhuang District, New Taipei City 248?"｜Document date: 2026-06-24; explains the 3+3 numbering principle: "the first 3 digits follow the administrative district of the delivery post office, and the last 3 digits are sequential delivery-segment numbers"; the first 3 digits do not always equal the district where the address is located.
- Chunghwa Post: notes on the use of this company's 3+3 postal code system｜Document date: 2026-04-14; 3+3 postal code data is "scheduled to be updated on the first day of each quarter", and the data file must be applied for through Chunghwa Post's file transfer management platform and sent with a stamp, "and can be downloaded only after approval"; it explains that the 3+3 data file requires a separate application and review.
- Chunghwa Post: Chunghwa Post Co., Ltd. "3+3 postal code" public license statement｜Document date: 2020-10-22; the 3+3 postal code is licensed to users "on a royalty-free, non-exclusive basis" and users "may publicly present the 3+3 postal code on any interface", but must not violate Chunghwa Post's software terms of use or the law.
- Chunghwa Post: 3+3 postal code lookup Web Service system integration application form｜Document date: 2024-01-03; the paper application for a different 3+3 postal code lookup Web Service: "integration IP (1 set, fixed)" and "only 1 record can be queried per request"; it is a different service from the NSDA WebAPI. HowBridge has submitted this application and it has not been approved.
- Government Open Data Platform: 3+3 postal codes (provider: Chunghwa Post Co., Ltd.)｜Document date: 2026-06-01; the dataset note states that the new "3+3 postal code" system has been implemented, with the implementation date converting to 2020-03-03; the provider is Chunghwa Post and the license is the Open Government Data License, version 1. The date is the metadata update date.
- Laws & Regulations Database: Postal Act, Articles 2 and 3｜Document date: 2023-06-28; Article 2: "the competent authority of this Act is the Ministry of Transportation and Communications"; Article 3: "to provide postal services, the Ministry of Transportation and Communications establishes the state-run Chunghwa Post Co., Ltd.".
- Laws & Regulations Database: Postal Act, Article 22｜Document date: 2023-06-28; "all kinds of mail shall be delivered to the address of the addressee written on its surface"; "mail that cannot be delivered shall be returned to the sender" — whether the address is correct directly affects delivery and returns.
- Laws & Regulations Database: Regulations Governing Mail Handling, Articles 18 and 56｜Document date: 2022-05-27; Article 56: "mail that cannot be delivered to the addressee or is refused by the addressee is undeliverable mail" and must be returned to the sender; Article 18: bulk mail on which "the postal code is written as required by Chunghwa Post and which is bundled by district may receive a discount".
- Laws & Regulations Database: Act Governing Chunghwa Post Co., Ltd., Article 1｜Document date: 2002-07-10; "the Ministry of Transportation and Communications establishes Chunghwa Post Co., Ltd. pursuant to Article 3 of the Postal Act", which explains the legal status of the operator of NSDA.
- Laws & Regulations Database: Personal Data Protection Act, Articles 2, 19 and 20｜Document date: 2025-11-11; Article 2 includes "means of contact" in personal data, so a delivery address is personal data; Article 19 requires a non-government agency collecting and processing data to have "a specific purpose"; Article 20 requires use "to be within the scope necessary for the specific purpose of collection".
- Laws & Regulations Database: Regulations Governing the Clearance of Air Express Cargo, Article 18｜Document date: 2026-02-23; where an express carrier declares in the name of the holder of imported goods, "except for documents, the consignee's name and address shall be declared"; the corresponding article in the regulations for sea express cargo is Article 19.
Research literature and international reports
Undeliverable as Addressed Mail (Report No. MS-AR-14-006)
The Postal Service handled over 158 billion pieces of mail in FY2013, of which nearly 6.8 billion pieces (4.3 percent) were undeliverable as addressed (UAA), at an estimated processing cost of $1.5 billion; causes include moves and illegible addresses, and the address accuracy of only 3 percent of mail was sampled by automated means. It shows that address errors are a quantifiable systemic cost.
Management Advisory – Strategies for Reducing Undeliverable as Addressed Mail (Report No. MS-MA-15-006)
In FY2014 there were 6.6 billion pieces (4.3 percent) of UAA, USPS processing cost nearly $1.5 billion, and the industry cost was about $20 billion a year; about 40 percent of UAA originated from individuals (mostly people who moved without notifying) and 35 percent from sending businesses that did not update their address lists. It supports the need for senders to verify addresses at the source.
Addressing the world – An address for everyone (White paper)
The Universal Postal Union white paper treats addresses and postal codes as infrastructure; it records a Costa Rican postal study finding that 40% of the addresses in business-customer databases were incorrect, and that the Danish government's opening of official address data in 2005–09 produced direct financial benefits of about 90 million USD against agreed costs of about 3 million USD.
Estimating the Economic Value of PAF® (Postcode Address File)
The UK Postcode Address File (PAF) is estimated to be worth £992m – £1.38bn a year to the UK economy, about 40% of it from postal and goods delivery; the report also lists misdelivery costs of about £100m for e-commerce due to poor address quality. The report itself describes its estimates as "necessarily speculative".
Improving home delivery efficiency by using principles of address intelligence for B2C deliveries
Dutch parcel-carrier data show that only 75% of first deliveries succeeded (recipient at home), with the other 25% counted as failed deliveries (15% handed to neighbors, 10% returned to the depot and redelivered), mainly because the recipient was not at home; using address-level historical data as "address intelligence" reduced rework by about 11% on average. Note: the main cause in this paper is the recipient not being home, not wrongly written addresses.
Carbon Dioxide Benefits of Using Collection–Delivery Points for Failed Home Deliveries in the United Kingdom
Simulating first-delivery failure rates of 10%, 30% and 50%, a second delivery attempt raises per-parcel carbon emissions by 9% to 75%; 85% to 95% of the carbon emissions of failed deliveries come from recipients traveling to the depot to collect parcels themselves. It shows that the cost of failed delivery is passed on to the recipient.
Usable error message presentation in the World Wide Web: Do not show errors right away
Two experiments (77 and 90 participants) found that "immediate error feedback", recommended by international standards, performed worst, and users often simply ignored the messages. Check results should be made visible and understandable, not just flashed briefly.
User-friendly locations of error messages in web forms: Put them on the right side of the erroneous input field
An online experiment with 303 participants: error messages placed near the erroneous field were clearly better than those at the top or bottom of the form; placement to the right of the field was the most preferred in subjective ratings. It can serve as a reference for where to place the address-field check prompt.
Designing usable web forms: Empirical evaluation of web form improvement guidelines
An eye-tracking experiment (N = 65) showed that improving forms according to design guidelines led to faster completion and fewer submission attempts. It supports using good form design to reduce address-entry errors.
Preparation of name and address data for record linkage using hidden Markov models
Address formats vary, so they must be "standardized" before matching; standardizing Australian addresses with dictionary-based tokenization plus hidden Markov models was as accurate as or better than commonly used rule-based systems. It shows that address standardization is a prerequisite step for matching and verification.
Using an Optimized Chinese Address Matching Method to Develop a Geocoding Service: A Case Study of Shenzhen, China
Chinese addresses have no delimiters and are managed by multiple agencies, which makes matching hard; this study built a geocoding service using an address model, address-tree standardization and matching, tested on more than 1,460,000 Shenzhen records. It shows that Chinese addresses must first be broken into components before being matched against a standard database.
A deep learning architecture for semantic address matching
Traditional matching looks only at literal similarity and struggles with unstructured addresses; word2vec plus ESIM was used to judge whether two addresses match, reaching precision, recall and F1 of 0.97 on a Shenzhen address-database test set. It shows that different writings of the same address need a semantic-level match.
Construction, Maintenance and Application of Address Coding
The report finds that, when datasets are matched against the compiled address data, Taipower has the lowest match rate at 88.91%, all others are above 96%, and household registration data is highest at 99.59%; it also states that "household-registration house-number addresses and postal addresses are not necessarily the same", and therefore includes Chunghwa Post's standard postal addresses.
The verification flow reflects the HowBridge server code as of 2026-10-05; the test results are 12 direct calls made that day and do not represent all addresses at Chunghwa Post. The official NSDA pages do not state fees, service levels or data update frequency, and this page does not infer them. Chunghwa Post and the Ministry of Transportation and Communications do not publish return statistics caused by address errors, and this page cites no Taiwan return rate.
What are the common questions about postal address checking?
Does HowBridge use Chunghwa Post's address service?
Does this mean Chunghwa Post certifies or endorses HowBridge?
What does "Postal standard address" on the screen mean?
Will the check stop me from saving?
Why is the floor missing from the check result even though I wrote one?
If Chunghwa Post cannot find it, is the address wrong?
Where can I see the 6-digit postal code?
Does HowBridge already use the 3+3 postal code Web Service?
Are my name and phone number sent to Chunghwa Post?
Are convenience-store pickup addresses checked too?
Further reading
Fill in your delivery address and have it checked first
Add or confirm a Taiwan delivery address in the member center. When you see "Postal standard address" or "House-number address matched", the way the address is written matches official data.
Enter your delivery address in the member center