Before submitting, make sure you've checked the following:
Target branch: Verify that the pull request targets the dev branch. PRs targeting main will be immediately closed.
Description: Provide a concise description of the changes made in this pull request down below.
Changelog: Ensure a changelog entry following the format of Keep a Changelog is added at the bottom of the PR description.
Documentation: Add docs in Open WebUI Docs Repository. Document user-facing behavior, environment variables, public APIs/interfaces, or deployment steps.
Dependencies: No new or upgraded dependencies.
Testing: Manually tested the feature against a live Open WebUI instance — confirmed {{chat_id}} is interpolated correctly in outgoing request headers, static headers are unaffected, unknown tokens are left as-is, and non-string values are coerced to strings without error.
Agentic AI Code: This PR was written with AI assistance and has gone through additional human review and manual testing.
Code review: Self-review performed.
Design & Architecture: No new settings or architectural changes — pure backend string substitution, fully backwards compatible.
Git Hygiene: Single logical change, rebased on dev.
Title Prefix: Title uses feat: prefix.
Changelog Entry
Description
Admins can now use {{chat_id}}, {{message_id}}, {{user_id}}, and {{user_name}} as dynamic placeholders in custom header values for OpenAI-compatible connections. This allows per-request context (like the current chat UUID) to be forwarded to upstream providers that use session-scoped headers for routing.
Tooltip in the Add/Edit Connection modal documenting the supported dynamic variables
Changed
Non-string custom header values are now coerced to str before being sent (aiohttp requires string header values)
Fixed
Non-string values in the custom headers config (e.g. integers) previously caused a serialization error at request time
Additional Information
The interpolation is done in get_headers_and_cookies() in backend/open_webui/routers/openai.py, just before custom headers are merged into the outgoing request. The metadata and user objects are already available at that point — no signature changes were needed.
Plain str.replace — no template engine, no logic, no new dependencies
Header values with no {{...}} tokens pass through unchanged — fully backwards compatible
Unknown tokens (e.g. {{foo}}) are left as-is, no error is raised
Motivation: Providers like Manifest use a session-scoped header (e.g. x-session-key) to scope routing state to a conversation. Without dynamic header values, each message in an Open WebUI conversation is treated as a new session on the provider side, losing any routing momentum built up across turns. With this change, an admin can configure {"x-session-key": "{{chat_id}}"} and every request will automatically carry the real chat UUID.
Contributor License Agreement
By submitting this pull request, I confirm that I have read and fully agree to the Contributor License Agreement (CLA), and I am providing my contributions under its terms.
🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.
## 📋 Pull Request Information
**Original PR:** https://github.com/open-webui/open-webui/pull/24164
**Author:** [@alejandroiglesias](https://github.com/alejandroiglesias)
**Created:** 4/27/2026
**Status:** 🔄 Open
**Base:** `dev` ← **Head:** `feat/dynamic-header-template-vars`
---
### 📝 Commits (10+)
- [`fe6783c`](https://github.com/open-webui/open-webui/commit/fe6783c16699911c7be17392596d579333fb110c) Merge pull request #19030 from open-webui/dev
- [`fc05e0a`](https://github.com/open-webui/open-webui/commit/fc05e0a6c5d39da60b603b4d520f800d6e36f748) Merge pull request #19405 from open-webui/dev
- [`e3faec6`](https://github.com/open-webui/open-webui/commit/e3faec62c58e3a83d89aa3df539feacefa125e0c) Merge pull request #19416 from open-webui/dev
- [`9899293`](https://github.com/open-webui/open-webui/commit/9899293f050ad50ae12024cbebee7e018acd851e) Merge pull request #19448 from open-webui/dev
- [`140605e`](https://github.com/open-webui/open-webui/commit/140605e660b8186a7d5c79fb3be6ffb147a2f498) Merge pull request #19462 from open-webui/dev
- [`6f1486f`](https://github.com/open-webui/open-webui/commit/6f1486ffd0cb288d0e21f41845361924e0d742b3) Merge pull request #19466 from open-webui/dev
- [`d95f533`](https://github.com/open-webui/open-webui/commit/d95f533214e3fe5beb5e41ec1f349940bc4c7043) Merge pull request #19729 from open-webui/dev
- [`a727153`](https://github.com/open-webui/open-webui/commit/a7271532f8a38da46785afcaa7e65f9a45e7d753) 0.6.43 (#20093)
- [`6adde20`](https://github.com/open-webui/open-webui/commit/6adde203cd292a9e3af9c64a2ae36b603fed096a) Merge pull request #20394 from open-webui/dev
- [`f9b0534`](https://github.com/open-webui/open-webui/commit/f9b0534e0c442631d1cb7205169588b9b6204179) Merge pull request #20522 from open-webui/dev
### 📊 Changes
**2 files changed** (+15 additions, -2 deletions)
<details>
<summary>View changed files</summary>
📝 `backend/open_webui/routers/openai.py` (+14 -1)
📝 `src/lib/components/AddConnectionModal.svelte` (+1 -1)
</details>
### 📄 Description
**Before submitting, make sure you've checked the following:**
- [x] **Target branch:** Verify that the pull request targets the `dev` branch. **PRs targeting `main` will be immediately closed.**
- [x] **Description:** Provide a concise description of the changes made in this pull request down below.
- [x] **Changelog:** Ensure a changelog entry following the format of [Keep a Changelog](https://keepachangelog.com/) is added at the bottom of the PR description.
- [ ] **Documentation:** Add docs in [Open WebUI Docs Repository](https://github.com/open-webui/docs). Document user-facing behavior, environment variables, public APIs/interfaces, or deployment steps.
- [x] **Dependencies:** No new or upgraded dependencies.
- [x] **Testing:** Manually tested the feature against a live Open WebUI instance — confirmed `{{chat_id}}` is interpolated correctly in outgoing request headers, static headers are unaffected, unknown tokens are left as-is, and non-string values are coerced to strings without error.
- [x] **Agentic AI Code:** This PR was written with AI assistance and has gone through additional human review and manual testing.
- [x] **Code review:** Self-review performed.
- [x] **Design & Architecture:** No new settings or architectural changes — pure backend string substitution, fully backwards compatible.
- [x] **Git Hygiene:** Single logical change, rebased on `dev`.
- [x] **Title Prefix:** Title uses `feat:` prefix.
# Changelog Entry
### Description
Admins can now use `{{chat_id}}`, `{{message_id}}`, `{{user_id}}`, and `{{user_name}}` as dynamic placeholders in custom header values for OpenAI-compatible connections. This allows per-request context (like the current chat UUID) to be forwarded to upstream providers that use session-scoped headers for routing.
> 💬 Community discussion: https://github.com/open-webui/open-webui/discussions/24165
### Added
- Template variable interpolation in custom connection headers: `{{chat_id}}`, `{{message_id}}`, `{{user_id}}`, `{{user_name}}`
- Tooltip in the Add/Edit Connection modal documenting the supported dynamic variables
### Changed
- Non-string custom header values are now coerced to `str` before being sent (aiohttp requires string header values)
### Fixed
- Non-string values in the custom headers config (e.g. integers) previously caused a serialization error at request time
---
### Additional Information
The interpolation is done in `get_headers_and_cookies()` in `backend/open_webui/routers/openai.py`, just before custom headers are merged into the outgoing request. The `metadata` and `user` objects are already available at that point — no signature changes were needed.
- Plain `str.replace` — no template engine, no logic, no new dependencies
- Header values with no `{{...}}` tokens pass through unchanged — fully backwards compatible
- Unknown tokens (e.g. `{{foo}}`) are left as-is, no error is raised
**Motivation:** Providers like [Manifest](https://manifest.build/) use a session-scoped header (e.g. `x-session-key`) to scope routing state to a conversation. Without dynamic header values, each message in an Open WebUI conversation is treated as a new session on the provider side, losing any routing momentum built up across turns. With this change, an admin can configure `{"x-session-key": "{{chat_id}}"}` and every request will automatically carry the real chat UUID.
### Contributor License Agreement
- [x] By submitting this pull request, I confirm that I have read and fully agree to the [Contributor License Agreement (CLA)](https://github.com/open-webui/open-webui/blob/main/CONTRIBUTOR_LICENSE_AGREEMENT), and I am providing my contributions under its terms.
---
<sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>
Blocking a user prevents them from interacting with repositories, such as opening or commenting on pull requests or issues. Learn more about blocking a user.
📋 Pull Request Information
Original PR: https://github.com/open-webui/open-webui/pull/24164
Author: @alejandroiglesias
Created: 4/27/2026
Status: 🔄 Open
Base:
dev← Head:feat/dynamic-header-template-vars📝 Commits (10+)
fe6783cMerge pull request #19030 from open-webui/devfc05e0aMerge pull request #19405 from open-webui/deve3faec6Merge pull request #19416 from open-webui/dev9899293Merge pull request #19448 from open-webui/dev140605eMerge pull request #19462 from open-webui/dev6f1486fMerge pull request #19466 from open-webui/devd95f533Merge pull request #19729 from open-webui/deva7271530.6.43 (#20093)6adde20Merge pull request #20394 from open-webui/devf9b0534Merge pull request #20522 from open-webui/dev📊 Changes
2 files changed (+15 additions, -2 deletions)
View changed files
📝
backend/open_webui/routers/openai.py(+14 -1)📝
src/lib/components/AddConnectionModal.svelte(+1 -1)📄 Description
Before submitting, make sure you've checked the following:
devbranch. PRs targetingmainwill be immediately closed.{{chat_id}}is interpolated correctly in outgoing request headers, static headers are unaffected, unknown tokens are left as-is, and non-string values are coerced to strings without error.dev.feat:prefix.Changelog Entry
Description
Admins can now use
{{chat_id}},{{message_id}},{{user_id}}, and{{user_name}}as dynamic placeholders in custom header values for OpenAI-compatible connections. This allows per-request context (like the current chat UUID) to be forwarded to upstream providers that use session-scoped headers for routing.Added
{{chat_id}},{{message_id}},{{user_id}},{{user_name}}Changed
strbefore being sent (aiohttp requires string header values)Fixed
Additional Information
The interpolation is done in
get_headers_and_cookies()inbackend/open_webui/routers/openai.py, just before custom headers are merged into the outgoing request. Themetadataanduserobjects are already available at that point — no signature changes were needed.str.replace— no template engine, no logic, no new dependencies{{...}}tokens pass through unchanged — fully backwards compatible{{foo}}) are left as-is, no error is raisedMotivation: Providers like Manifest use a session-scoped header (e.g.
x-session-key) to scope routing state to a conversation. Without dynamic header values, each message in an Open WebUI conversation is treated as a new session on the provider side, losing any routing momentum built up across turns. With this change, an admin can configure{"x-session-key": "{{chat_id}}"}and every request will automatically carry the real chat UUID.Contributor License Agreement
🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.